jueves, 28 de abril de 2011

Hacking VW CAN-Comfort Bus III - HOW-TO

The best explication.... a video!!
You can watch a easy method when you haven´t too many messages, like in the Comfort-CAN Bus.

I´ve used for the example an USB <--> Can Bus converter from PEAK, but it´s easy to do exactly the same using your Arduino + brick. A small software it´s in my TODO list!!!

Sometimes, I´ve used my Arduino + brick saving the console output in a *.csv . You need to send properly (fields separated by comma). You can use Excel or unix commands like grep for the post-processing!!!

I hope you enjoy with the following video!!

Video Tutorial:

NEW INFO !!

I´ve tried to monitor what happens when the car starts to move.... and some bytes start to "dance"!!! Could be the speed? Let´s go to record some small test to achieve enought information (constant speed)...Yes it is!!!

Thanks to this constant speed tests, I´ve been able to discover the "gain" applied. Because the raw value is like the rpm counter. Maybe this value it´s not 100% correct as it has calculated experimentally.
I've used excel to help me filtering, doing the small math calculus and graphing.

There is another channel in that message that follows very good the speed. Could be the ticks or something similar from the timer? Any idea?

3 comentarios:

Anónimo
dijo...

the red unknown graph could be raw input from either one of the ABS sensors on one of the wheels... or the vehicle speed sensor in the gearbox. I believe both of the sensors I've mentioned are glorified rotary encoders (I could easily be wrong). Good luck